Technical Field
The present disclosure relates to an electric power measuring system, and more particularly, to an electric power measuring system capable of computing accurate electric power information using a low voltage measuring instrument in a small-scale electric power system.
Description of the Related Art
Generally, an electric power measuring system measures a voltage and a current flowing at an electric power system in a distribution panel or a panel board, that is, a load of a distribution line to compute electric power information such as electric energy and the like through various computations.
The electric power measuring system includes a measuring instrument for measuring a voltage and an amount of a current from a distribution line to generate various measuring information. The measuring instrument is classified into a high voltage measuring instrument and a low voltage measuring instrument.
The high voltage measuring instrument measures all of a voltage and an amount of a current from a distribution line to generate first data, for example, data including voltage information, current information, power factor information and the like, and processes the first data to generate second data, for example, electric power information of the distribution line. The low voltage measuring instrument measures one of a voltage and an amount of a current from a distribution line to generate first data.
Meanwhile, in a small-scale distribution panel or panel board, an electric power measuring system is established with only a low voltage measuring instrument due to a manufacture cost factor. And, the low voltage measuring instrument measures one of a voltage and an amount of a current of a distribution line and generates first data according to the measurement to transmit the first data to an external side through a communication.
FIG. 1 is a diagram schematically illustrating a configuration of a typical electric power measuring system.
As shown in FIG. 1, a typical electric power measuring system 1 includes a low voltage measuring instrument, that is, a current measuring instrument 20 which measures a current from a distribution line 10 to generate current information I in a distribution panel or a panel board.
In the distribution line 10 configured with a three-phase balanced line having phase terminals of an R-phase, an S-phase, and a T-phase, the current measuring instrument 20 measures a current value with respect to one of the R-, S-, and T-phases. The current measuring instrument 20 generates the current information I of the distribution line 10 from the measured current value to transmit the current information I to an integrated measuring instrument 30 of an external side through a communication.
The integrated measuring instrument 30 computes electric power information P of the distribution line 10 from the current information I transmitted from the current measuring instrument 20 on the basis of voltage information V, for example, alternating current (AC) voltage information of the distribution line 10, provided from the external side. The electric power information P is information regarding an AC electric energy.
As described above, in the typical electric power measuring system 1, the current measuring instrument 20 is installed inside the distribution panel or the panel board, and the current information I of the distribution line 10 is transmitted from the current measuring instrument 20 to the integrated measuring instrument 30 of the external side to compute the electric power information P of the distribution line 10.
In the typical electric power measuring system 1, however, when the current measuring instrument 20 transmits the current information I to the integrated measuring instrument 30, a problem in which a phase of the current information I is not synchronized with that of the voltage information V may occur due to a time delay and the like.
As a result, when the integrated measuring instrument 30 computes the electric power information P of the distribution line 10, a phase error between the voltage and the current may occur in the typical electric power measuring system 1. Consequently, it is difficult to accurately compute the electric power information P of the distribution line 10 to cause a problem in which reliability of the typical electric power measuring system 1 is degraded.